In 1946, she made her first recordings, for Haven Records with the masters soon purchased by Signature Records,[6] as a member of The Sunset Four.(aka.The Sunset Jubilee Singers) Shortly afterwards, Sister Rosetta Tharpe saw her singing at the Golden Gate Auditorium in Harlem, on a bill with Mahalia Jackson, and invited Knight to join her on tour.[2] Tharpe recognized "something special" in Marie's contralto voice.[3]

She continued to record and perform with Tharpe through the 1940s, sometimes acting out the parts of "the Saint and the Sinner", with Tharpe as the saint and Knight as the sinner.[2] Among their successes were the songs "Beams of Heaven", "Didn't it Rain", and "Up Above My Head", recorded for Decca Records. "Up Above My Head", credited jointly to both singers, reached No. 6 on the US R&B chart at the end of 1948, and Knight's solo version of "Gospel Train" reached No. 9 on the R&B chart in 1949.[7]

She left Tharpe to go solo around 1951, and put together a backing group, The Millionaires (Thomasina Stewart, Eleonore King and Roberta Jones), with whom she recorded the 1956 album Songs of the Gospel.[2] She began recording secularR&B music in the late 1950s, for various labels including Decca, Mercury, and Okeh. Her duet with Rex Garvin, credited as Marie & Rex, "I Can't Sit Down" released on the Carlton label, reached No. 94 on the pop chart in 1959.[8][9] In the late 1950s she also toured Britain as a guest of Humphrey Lyttelton.[2]

She toured with Brook Benton, the Drifters, and Clyde McPhatter, and regularly reunited onstage with Tharpe.[3] She remained friends with Tharpe, and helped arrange her funeral in 1973. In 1975, having given up performing secular music, she recorded another gospel album, Marie Knight: Today. In 2002, Knight made a comeback in the gospel world, recording for a tribute album to Tharpe. She released a full-length album, Let Us Get Together, on her manager's label in 2007.[2]